Dunhuang, a 2,000-year-old city in northwest China, is now at the forefront of China's green energy drive.

It's home to the nation's largest photothermal power plant, capable of storing solar energy for uninterrupted power supply. The power plant boasts a massive 100-megawatt installed capacity.

One special feature is its use of movable mirrors called heliostats, each covering a vast area of 115 square meters.